In a magnetic storage device which uses a magnetic disk, magnetic tape, or other medium as a recording medium (hereinafter referred to as a magnetic recording medium), a data write magnetic head magnetizes a magnetizable material coated on a disk or tape so as to record data in the form of a magnetic pattern which varies with the magnetic strength. To perform a data read, a data read magnetic head reads a magnetic pattern remaining in the magnetizable material of the magnetic recording medium as a signal and decodes the read signal. The magnetic storage device reads/writes data while the magnetic heads are in contact with or slightly apart from the magnetic recording medium.
As described above, the magnetic storage device records data in the form of a magnetic pattern, which is obtained by magnetizing the magnetizable material of the magnetic recording medium. To read/write data accurately, it is essential that the distance between the magnetic heads and magnetic recording medium be fixed. However, if dust or dirt enters the space between the magnetic heads and magnetic recording medium, the distance between the magnetic heads and magnetic recording medium becomes variable, thereby adversely affecting the data read/write performance. Typical adverse influences would be amplitude changes and phase changes in a read signal and write signal as discussed by Sarigoz et al., Fatih Sarigoz, Gang Li, B. V. K. Vijaya Kumar, James A. Barin, Jian-Gang Zhu, “Analysis of Dropout Peakshift in Magnetic Tape Recording”, IEEE TRANSACTIONS ON MAGNETICS, Vol. 36, No. 5, September 2000
As described above, the read/write performance of the magnetic storage device may deteriorate if the distance between the magnetic heads and magnetic recording medium becomes variable due to dust or dirt existence between them. When a data read operation is adversely affected and rendered unsuccessful, a data read can be performed again. However, if a data write operation is adversely affected, the loss of recorded data readability or other serious problem may arise.
Particularly if the phase of a write signal is significantly shifted due, for instance, to the influence of dust or dirt during data recording onto a magnetic recording medium, data is recorded on the magnetic recording medium with the phase shifted. Consequently, when the data is read, the resulting read signal contains a significant phase shift so that desired data cannot be obtained.
In recent years, the magnetic disk's data recording density has been remarkably increased in order to increase the capacity of a magnetic disk device. Therefore, an increased degree of data read accuracy is called for. As a result, it is now necessary to effectively avert the aforementioned influence of dust/dirt inclusion between the magnetic heads and magnetic recording medium.